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阵列信号处理中的空间谱估计可以对信号源进行辨别和定位,于是通过采集在结构上布置的阵列传感器Lamb波信号用来检测损伤发生的位置。通常,大多数空间谱估计方法均以窄带信号为假定,在很多基于Lamb波的结构损伤检测中,为了减小频散特性的影响,大多数研究以Lamb波为窄带信号进行分析,但无限窄的激励信号是物理不可实现的。因此,其在多数情况下Lamb波信号并不符合窄带信号假定,更应被认为是一种宽带信号来进行处理。进而利用空间谱估计中宽带信号非相干子空间处理方法(Incoherent Signal Subspace Method,ISM)中阵列接收的宽带Lamb波信号进行处理,检测出结构发生单一损伤时的损伤位置。随后,当结构损伤与边界反射波有叠加时会引起损伤信号相干,采用宽带信号相干子空间方法(Coherent Signal Subspace Method,CSM)对损伤位置进行检测,得到了较好的结果。
The spatial spectrum estimation in array signal processing can identify and locate the signal source, and then detect the location of the damage by collecting the structurally arranged array sensor Lamb wave signals. In general, most spatial spectrum estimation methods are based on narrow-band signals. In many structural damage detection based on Lamb waves, in order to reduce the influence of dispersion characteristics, most studies use Lamb wave to analyze narrowband signals, The excitation signal is physically unrealizable. Therefore, in most cases, the Lamb wave signal does not meet the narrowband signal assumption, and should be considered as a wideband signal for processing. Then, a wideband Lamb wave signal received by the array in the Incoherent Signal Subspace Method (ISM) is used to process the spatial spectrum estimation, and a damage location when the structure is damaged by a single structure is detected. Subsequently, when the structural damage and the boundary reflection wave are superimposed, the damage signal will be caused to be coherent. The Coherent Signal Subspace Method (CSM) is used to detect the damage location, and good results are obtained.